docs: def Nishino_Yamazaki(x, rhol, rhog):
      r'''Calculates void fraction in two-phase flow according to the model
      presented in [1]_ as shown in [2]_.
  
      .. math::
          \alpha = 1 - \left(\frac{1-x}{x}\frac{\rho_g}{\rho_l}\right)^{0.5}
          \alpha_h^{0.5}
          
      Parameters
      ----------
      x : float
          Quality at the specific tube interval []
      rhol : float
          Density of the liquid [kg/m^3]
      rhog : float
          Density of the gas [kg/m^3]
  
      Returns
      -------
      alpha : float
          Void fraction (area of gas / total area of channel), [-]
  
      Notes
      -----
      [1]_ is in Japanese. 
      
      [3]_ either shows this model as iterative in terms of voidage, or forgot
      to add a H subscript to its second voidage term; the second is believed
      more likely.
  
      Examples
      --------
      >>> Nishino_Yamazaki(.4, 800, 2.5)
      0.931694583962682
  
      References
      ----------
      .. [1] Nishino, Haruo, and Yasaburo Yamazaki. "A New Method of Evaluating 
         Steam Volume Fractions in Boiling Systems." Journal of the Atomic Energy
         Society of Japan / Atomic Energy Society of Japan 5, no. 1 (1963): 
         39-46. doi:10.3327/jaesj.5.39.
      .. [2] Xu, Yu, and Xiande Fang. "Correlations of Void Fraction for Two-
         Phase Refrigerant Flow in Pipes." Applied Thermal Engineering 64, no. 
         1-2 (March 2014): 242–51. doi:10.1016/j.applthermaleng.2013.12.032. 
      .. [3] Woldesemayat, Melkamu A., and Afshin J. Ghajar. "Comparison of Void 
         Fraction Correlations for Different Flow Patterns in Horizontal and 
         Upward Inclined Pipes." International Journal of Multiphase Flow 33, 
         no. 4 (April 2007): 347-370. doi:10.1016/j.ijmultiphaseflow.2006.09.004.
      '''
      alpha_h = homogeneous(x, rhol, rhog)
      return 1 - ((1-x)*rhog/x/rhol)**0.5*alpha_h**0.5